Reincarnated AAN Block.How to remove Rust?

[popdemonic]

Today i just got this volunteer for a rebuilt.it's an AAN block.
I still can see the crosshatch on the cylinder walls.The problem is
the head being removed for a couple months so the moist caused some
surface rust on the rods on the crankshaft(not terrible).I'm going to use
some 4000grids sandpaper mildly penetrated on them but the cylinder walls
and the upper block surface that directly contacted the head is having
fair amount of rust on them.I'm not sure if it's going to cause some pits.
on them.What's the best way to get them done.Do you think i need oversized
pistons on this case?If i need oversized pistons I'd consider to keep this block away
and use another AAN blocks.

[macspring]

Why wasn't it kept in your bedroom like the rest of us do, with our spare S parts ?

Best wishes.

[K Simmonds]

The bore's look like they 'may', and I stress may, be just be OK with hone but it's very hard to tell from a photo. The block deck will need to be resurfaced and I'd imagine the crack journals will need polishing at the very least though it's likely it will need to be reground.

[popdemonic]

Why wasn't it kept in your bedroom like the rest of us do, with our spare S parts ?

Best wishes.

The poor Mechanic just neglected this block and don't proper keep this block away from moist.He didn't even realize this's valuable belongings of the rest S-cars survival in my country.Now I bring it to the good home.

[popdemonic]

The bore's look like they 'may', and I stress may, be just be OK with hone but it's very hard to tell from a photo. The block deck will need to be resurfaced and I'd imagine the crack journals will need polishing at the very least though it's likely it will need to be reground.

I think I'd better send this survivor to the Machine shop and pay him $100 for a polishing and honing job.Only thing i'm concerned is i don't want to get it overbored which means it requires another set of oversized rings.I still have 8 of AAN stock pistons with
new set of the stock rings and I tend to use them.

This is my "Minor Project" and should be my one last project on this car.I'm getting the used Gearbox from Germany at the moment.My stock AAN engine recently got the worn
valve guides.I'm thinking to pull them out at the same time.I'm thinking to rebuild my full motor with stock application.I don't think i'd go for a stroker since I'm living in Thailand.There's only a fews I5 cars here so just don't imagine about the used parts
availability.I don't know how long could i own this car but i would like to reach my 440 crank HP before the car might be sold in one day.My car already had GT2871,VEMS and all necessary/supported parts

[macspring]

Ask a good machine shop to save it, as the cost will be cheaper than you obtaining a replacement ?

A bird in the hand is worth two in the bush.

[Error404]

That doesn't look too bad! My block was actually much worse after many years standing empty in a damp environment and it cleaned up OK
I used this trick with molasses to remove almost all the corrosion, inside the water jacket too. Wire brush off the surface first, then submerge in 1 part molasses to 10 parts water. Leave it to soak for 2 weeks then wash off with water

You will probably find that bores are OK after this and a hone. You will need to resurface the deck, but you will do this & hone anyway when you build up the engine

I also decided to give it a go with the old AAN block kindly donated by Pix. It had some sever corrosion in the water jacket, and some severe pitting in the deck around the water channels, probably caused by running pure tap water in the cooling system in it for a long period of time. Anyway, again me and wire brush have been busy. Then I saw online that you could use molasses to remove rust - I thought a total immersion would be the only way to get the scale & corrosion out of the water jacket, so I took a punt and bought 10L of the stinky stuff from my local horse feed shop. They thought I was nuts
We will see how it works in a few days when I pull it out. Shame I never got a before shot, but I am sure Pix will testify to it looking like he'd just dug it out the ground Thanks again mate

Got a bit more done on the old banger today.

Pulled the old block out of its stinking sticky pickle and its done a really good job of dissolving the corrosion! Virtually all gone, except a few spots where it was really thick. It flash rusted in seconds once I'd washed it off, so I knew it was clean. It had been bubbling away for a week.






A few spots like this remained, but I am confident with another week in the molasses it would be back to clean metal:
I'll get some paint on the block tomorrow then I can get it decked, bored & honed.

[macspring]

Hi Alex,

That's a cool trick.

Any link to the type of molasses you used, or is molasses just molasses from any equestrian equipment suppler ?

Everyday's a school day on here.

I 'think' I understand electrolysis, but do you know how this works ?

Thanks again either way.

[popdemonic]

Honestly i never heard any of Molasses Rust removal before but i'm so uch impressive with the result.Amazing!

[Error404]

I bought it from a horse feed shop - they use it to supplement the nag's diet I think. As far as I know molasses is molasses, its a byproduct of refining sugar cane i think.
I believe it is a chemical reaction, from what I gather some acid or other in the molasses strips the oxygen from the iron oxide (rust) leaving behind a kind of black sludge that just rinses off

[Thuppu]

Good thread, I also just doing a budget build of leftover scrap found in the garage. Thread hijacking.

Just want to be sure. Stock bore size is exact 81.00mm with a wear limit of max. 0.08mm. Stock pistons size is 80.98mm with a wear limit of max. 0.04mm. Is this correct?

[macspring]

I bought it from a horse feed shop - they use it to supplement the nag's diet I think. As far as I know molasses is molasses, its a byproduct of refining sugar cane i think.
I believe it is a chemical reaction, from what I gather some acid or other in the molasses strips the oxygen from the iron oxide (rust) leaving behind a kind of black sludge that just rinses off

Can't wait to try it !

Any more gems ?

Like a quick rack on a RHD C4 ?

[popdemonic]

What paint you guy using on the block?VHT or something for heat resistance?

[Error404]

I used POR15 as a primer, then POR15 engine enamel, then that was too shiney so i scotched it and finished with some 2k satin black for good measure!

[popdemonic]

the problem is now where can i get those molasses in my country lol.